Methods and systems for removing acetone from olefin-containing hydrocarbon streams

Abstract

Disclosed are methods and systems for removing acetone from olefin-containing hydrocarbon streams. In one embodiment, a method for removing acetone from a hydrocarbon stream includes mixing an olefin-containing hydrocarbon stream and a wash water stream to form a mixed olefin/wash water stream, wherein the olefin-containing hydrocarbon stream comprises acetone impurities, and wherein mixing comprises dissolving at least a portion of the acetone impurities in to the wash water stream, coalescing the mixed olefin/water stream to separate the wash water stream with acetone dissolved therein from the hydrocarbon stream, wherein the separated hydrocarbon stream comprises non-coalesced wash water and acetone, and drying the separated hydrocarbon stream to remove at least a portion of the non-coalesced wash water and acetone therefrom and to form a dried hydrocarbon product stream.

What is claimed is: 
     
         1 . A method for removing acetone from a hydrocarbon stream comprising the steps of:
 mixing an olefin-containing hydrocarbon stream and a wash water stream to form a mixed olefin/wash water stream, wherein the olefin-containing hydrocarbon stream comprises acetone impurities, and wherein mixing comprises dissolving at least a portion of the acetone impurities in to the wash water stream;   coalescing the mixed olefin/water stream to separate the wash water stream with acetone dissolved therein from the hydrocarbon stream, wherein the separated hydrocarbon stream comprises non-coalesced wash water and acetone;   drying the separated hydrocarbon stream to remove at least a portion of the non-coalesced wash water and acetone therefrom and to form a dried hydrocarbon product stream;   recycling a portion of the dried hydrocarbon product stream to form a product regeneration stream; and   mixing the product regeneration stream with at least a portion of the olefin-containing hydrocarbon stream and the wash water stream.   
     
     
         2 . The method of  claim 1 , wherein mixing comprises mixing the hydrocarbon stream and the wash water at a ratio of water to hydrocarbons of less than 0.3:1, by volume. 
     
     
         3 . The method of  claim 1 , wherein coalescing comprises coalescing in a packed-bed coalescer. 
     
     
         4 . The method of  claim 1 , further comprising recycling the separated wash water stream. 
     
     
         5 . The method of  claim 1 , further comprising passing the separated wash water stream to an alkylate wash tower of a downstream hydrocarbon alkylation system. 
     
     
         6 . The method of  claim 1 , wherein drying comprises drying in a lead/lag dehydration unit. 
     
     
         7 . The method of  claim 6 , wherein drying comprises drying in a lead dryer unit comprising an adsorbent or dessicant. 
     
     
         8 . The method of  claim 7 , further comprising regenerating spent adsorbent or dessicant in a lag dryer unit. 
     
     
         9 . The method of  claim 8 , wherein recycling the portion of the dried hydrocarbon product stream comprises recycling to the lag dryer unit. 
     
     
         10 . The method of  claim 1 , further comprising passing the dried hydrocarbon product stream to a hydrocarbon alkylation system. 
     
     
         11 . A system for removing acetone from a hydrocarbon stream comprising:
 a mixing unit that mixes an olefin-containing hydrocarbon stream and a wash water stream to form a mixed olefin/wash water stream, wherein the olefin-containing hydrocarbon stream comprises acetone impurities, and wherein mixing comprises dissolving at least a portion of the acetone impurities in to the wash water stream;   a coalescer unit that coalesces the mixed olefin/water stream to separate the wash water stream with acetone dissolved therein from the hydrocarbon stream, wherein the separated hydrocarbon stream comprises non-coalesced wash water and acetone; and   a dehydration unit that dries the separated hydrocarbon stream to remove at least a portion of the non-coalesced wash water and acetone therefrom and to form a dried hydrocarbon product stream, wherein the dehydration unit employs a recycle portion of the dried hydrocarbon product as a product regeneration stream.   
     
     
         12 . The system of  claim 11 , wherein the mixing unit comprises an in-line mixer, a scrubber, or a counter-current tower. 
     
     
         13 . The system of  claim 11 , wherein the coalescer unit comprises a packed-bed coalescer. 
     
     
         14 . The system of  claim 11 , wherein the dehydration unit comprises a lead/lag dryer system. 
     
     
         15 . The system of  claim 14 , wherein the lead/lag dryer system comprises an adsorbent or dessicant. 
     
     
         16 . The system of  claim 15 , wherein a lead dryer of the lead/lag dryer system produces the dried hydrocarbon product. 
     
     
         17 . The system of  claim 16 , wherein a lag dryer of the lead/lag dryer system receives the product regeneration stream. 
     
     
         18 . The system of  claim 17 , wherein the product regeneration stream regenerates the adsorbent or dessicant within the lag dryer. 
     
     
         19 . A method for removing acetone from an olefin-containing hydrocarbon stream comprising the steps of:
 mixing an olefin-containing hydrocarbon stream and a wash water stream to form a mixed olefin/wash water stream, wherein the olefin-containing hydrocarbon stream comprises acetone impurities, and wherein mixing comprises dissolving at least a portion of the acetone impurities in to the wash water stream;   coalescing the mixed olefin/water stream to separate the wash water stream with acetone dissolved therein from the hydrocarbon stream, wherein the separated hydrocarbon stream comprises non-coalesced wash water and acetone;   drying the separated hydrocarbon stream in a lead/lag dryer system comprising a lead dryer and a lag dryer to remove at least a portion of the non-coalesced wash water therefrom and to form a dried hydrocarbon product stream, wherein the dried hydrocarbon product stream is formed in a lead dryer of the lead/lag dryer system;   recycling a portion of the dried hydrocarbon product stream to form a product regeneration stream;   contacting the product regeneration stream with the lag dryer of the lead/lag dyrer system; and   after contacting, mixing the product regeneration stream with at least a portion of the olefin-containing hydrocarbon stream and the wash water stream.   
     
     
         20 . The method of  claim 19 , wherein contacting comprises regenerating an adsorbent or dessicant with the lag dryer of the lead lag dryer system.